When Did Mandatory Vaccinations Become Common?

New York Daily News Archive/Getty Images Joseph Burns, 8, grimaces as doctor vaccinates him at St. Joan of Arc Parochial School in Jackson Heights, Queens, New York, in 1947

Anti-Vaxxers are upset with mandatory Measles vaccinations. But mandatory vaccinations have a long history in the United States

History News Network

This post is in partnership with the History News Network, the website that puts the news into historical perspective. The article below was originally published at HNN.

Herbal panaceas, special cloths, strict diets, cool drinks, eschewing fireplaces, and the edict that a patient’s bedclothes be no higher than the patient’s waist—these were the prescriptions of the pre-inoculation era when someone contracted smallpox. For centuries pandemic diseases devastated much of mankind. Hardly more than a century ago, 20% of children fell to disease before the age of five, a staggering 20% more died before entering into adolescence, survivors finding little recourse in adulthood from the scourges of the age—diphtheria, yellow fever, small pox, measles, pertussis, and a deadly handful of others. It was in such a dire period that the first federal health mandates were made and bore the political origins of compulsory vaccination.

A string of yellow fever outbreaks erupted between 1793 and 1798, taking thousands of lives and leaving the nation dizzy with loss. Shortly after the outbreaks, John Adams signed and established the first federal quarantine law against the recurrent epidemics of yellow fever. According to Carleton B. Chapman, an MD, the Federal Quarantine Proposal of 1796 met “virtually no opposition.”

A couple of years later, in 1798, Congress returned to the issue after a high percentage of marine workers succumbed to yellow fever. For the first time ever,, Congress required privately employed sailors to own insurance and authorized the collection of a monthly payroll tax to fund it. John Adams promptly signed the law when it reached his desk.

Chapman states that few founders contested the federal government’s responsibility to protect the population from epidemics like yellow fever. The real issue, he reports, “was which level of government should enact and enforce quarantine.” This was the same question that arose years later when vaccination gained popularity in the medical field. Wendy K. Marine, George J. Annas, and Leonard Glantz explain that while Jeffersonians were uncomfortable with a strong federal role, Jefferson himself favored a bill that required the federal government to “guarantee and distribute effective vaccine” and signed it into law in 1813. Ultimately, Congress decided that the best approach was to leave the implementation of vaccination efforts up to state and local authorities.

America had many years of experience with vaccinations. The Puritans provided for vaccinations against smallpox after an outbreak devastated New England. But immunizations weren’t required anywhere in the United States until 1809, when Boston imposed mandatory vaccination to quell recurring outbreaks of smallpox that patchy, voluntary vaccination was permitting. Subsequently, some states adopted similar legislation. Scholars Alexandra Minna Stern and Howard Markel report that incidences of smallpox markedly declined between 1802 and 1840, but made major reappearances in the 1830s and 1870s when public memory of life imperiled by disease had dimmed and “irregular physicians” of the 1850s challenged the practice of immunization with “unorthodox medical theories.” One skeptical leader, British immigrant and reformer William Tebb, claimed, facts notwithstanding, that vaccination induced 80% of smallpox cases. Further, he alleged 25,000 children were “slaughtered” in Britain each year thanks to the program. The arguments were preposterous and contrary to evidence, but resonated with the public.

There’s a striking parallel to current anti-vaxxer scares playing on people’s fears, like the discredited and recanted study that alleged vaccination induced autism. Anti-vaccinationist Dr. J.F. Banton warned that vaccination would introduce “bioplasm” into the bloodstream and expose subjects to the “vices, passions, and diseases of the cow.” Stern and Markel relate that critics of vaccination claimed it was a “destructive and potentially defiling procedure of heroic medicine” akin to blood-letting. Many working-class people voiced the fear you hear today that the work of scientists was an “assault on their communities by the ruling class” and an “intrusion of their privacy and bodily integrity.”

The upshot? Smallpox cases surged to numbers that had not been seen in decades. Consequently, many states enacted new vaccination laws while others began enforcing existing laws. This, in turn, stirred increased opposition. California, Illinois, Indiana, Minnesota, Utah, West Virginia, and Wisconsin, repealed compulsory laws in response to the agitation.

Cambridge, Massachusetts found itself in the throes of a smallpox outbreak in 1902. Disease beset the area and threatened to spread into a major epidemic. To stop this from happening in the future the state passed a law giving city boards of health the authority to mandate vaccinations. But some people objected. When officials ordered Henning Jacobson, a Swedish immigrant and Lutheran pastor to be vaccinated, he refused treatment on grounds of past harm, saying both he and his son had experienced “extreme suffering.” Jacobson’s status as an ethnic and religious minority likely contributed to his decision to refuse treatment. His distrust of authority is shared today by many African Americans, who well remember that racist scientists performed experiments such as the Tuskegee syphilis study on people of color.

In a sense, Jacobson represented the quintessential anti-vaxxer, which may be why his case caught the eye of the anti-vaccination league, which encouraged Jacobson’s recalcitrance and may or may not have provided the Harvard-trained James W. Pickering and Henry Ballard to represent him in court. Eventually the case made its way to the United States Supreme Court. In 1905 the Supreme Court ruled 7-2 in favor of the state against Jacobson; the Court having found that an immunization rate of 85-90 percent confers protection on the entire group. The landmark Supreme Court case Jacobson v Massachusetts served as the precedent for future court decisions and the foundation of public health laws.

The Supreme Court considered the ordinance again in 1922 when some objected to the requirement that school children be vaccinated. Once again, the principle of mandatory vaccination was upheld. By 1969 compulsory immunization laws in twelve states—Georgia, Hawaii, Illinois, Kansas, Kentucky, Louisiana, Massachusetts, Michigan, Mississippi, Rhode Island, Tennessee, and West Virginia—had expanded to include smallpox, measles, poliomyelitis, diphtheria, pertussis, and tetanus. Meanwhile, seven states—Arizona, California, Minnesota, North Dakota, South Dakota, Utah, and Washington—found it unlawful to compel citizens to be vaccinated for smallpox while still requiring pre-enrollment immunization for other diseases like measles.

Since its inception compulsory public health laws have generated skepticism and resistance. Today, recent measles outbreaks—176 affected from January 1st to March 13th, 2015—have revitalized a long-lived debate and precipitated discussion about new approaches to public education.

Cristina Valldejuli, a graduate of the University of Iowa, is an HNN intern.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

Poor vaccination rates may be to blame for recent measles outbreak

The areas hit by the recent measles outbreak had vaccination rates as low as 50%, which allowed the disease to spread, new research suggests.

Researchers at Boston Children’s Hospital analyzed case numbers reported by the California Department of Public Health as well as other regional surveillance data to estimate the vaccination rates of areas affected by the measles outbreak in California, Arizona and Illinois. The team published a research letter of their findings in the journal JAMA Pediatrics.

The researchers found that the vaccination rates for the areas were somewhere between 50% to 86%, which is significantly lower than the 96%-to-99% rate needed to create herd immunity — when a significant portion of the population is protected so that there’s a low risk of an infectious-disease outbreak.

“Our data tell us a very straightforward story — that the way to stop this and future measles outbreaks is through vaccination,” said study author John Brownstein, of the Children’s Hospital Informatics Program, in a statement. “The fundamental reason why we’re seeing the number of cases we are is inadequate vaccine coverage among the exposed.”

Between Jan. 1 to March 13, 176 Americans were infected with measles and reported to the U.S. Centers for Disease Control and Prevention. Most of the people in the recent outbreak were not vaccinated, and many of the cases were linked to a Disneyland amusement park in California.

Why West Africa Might Soon Have 100,000 More Measles Cases

One lethal epidemic could give rise to another

Correction appended, March 12

There’s not a war college in the world that couldn’t learn a thing or two from the way viruses operate. They’re stealthy, they’re territorial, they seek and destroy and know just where to hit. And, just when you think you’ve got them beat, they forge an alliance with another of your enemies. That, according to a new paper published Thursday in Science, is what’s poised to happen with Ebola and measles—and it’s the babies and children of Africa who will overwhelmingly pay the price.

The Ebola epidemic is by no means over, but it is being contained and controlled. With nearly 24,000 cases and more than 9,800 fatalities so far—mostly in Guinea, Sierra Leone and Liberia—the epidemic is still claiming new victims, though more slowly. The crisis, however, has disrupted health-care delivery across the entire affected region, preventing children from receiving badly needed measles vaccines. That, the new study reports, could result in an additional 100,000 measles cases over the next 18 months, leading to an additional 2,000 to 16,000 deaths. Rates of vaccination against other diseases—particularly polio and tuberculosis—have fallen too. But measles’ ease of transmission makes it especially worrisome.

“When there’s a disruption of medical services, measles is always one of the first ones in the door,” says Justin Lessler, of the Johns Hopkins Bloomberg School of Public Health, a co-author of the paper. “The Ebola epidemic significantly increases the likelihood of a major measles outbreak occurring.”

Lessler and his co-authors arrived at their numbers painstakingly. First, they used health data to map and estimate the share of vaccinated and unvaccinated children in 5 km by 5 km (3.1 mi. by 3.1 mi.) squares across the three affected countries. They then estimated a 75% reduction in vaccination rates during the epidemic and projected forward by 6, 12 and 18 months. They factored in the transmissability of the virus within each region and estimated the likely number of deaths using what’s known as a Case Fatality Ratio—a mathematical tool that, as its name suggests, estimates lethality for any particular disease under any particular set of circumstances.

The final numbers—especially the potential 16,000 deaths—rightly alarmed the researchers, though lessler does admit that they are by no means a certainty. “The 75% decrease in vaccinations is a little too pessimistic,” he concedes. But the critical word in that admission is “little,” and the investigators did consider 25%, 50% and 100% rates too, before settling on 75% as at least the most plausible. No matter what, the odds are still high of a five figure death rate and a five to six figure additional case rate—and the Ebola epidemic, which led to the problem in the first place, has not even fully abated.

Lessler and his colleagues are not waiting until it does to sound the alarm, urging global health groups to mobilize a vaccination campaign now so it can be ready to launch in the affected areas the moment the Ebola all-clear sounds. The new push would first target children who were born during the Ebola epidemic since they would have likely received almost no medical attention at all up until that point, and then expand to all children in the most measles-susceptible age group—about 6 months to 5 years.

“The best time to start the campaign would be as soon as it’s logistically feasible,” says Lessler. “For every month no campaign begins, the risk of an outbreak occurring and the impact of such an outbreak worsens.”

The happy news, Lessler believes, is that done right, the campaign could not only prevent the measles epidemic from beginning, but could actually put West Africa in a better position than it was before Ebola, with vaccine coverage for measles and other diseases exceeding the pre-outbreak rates. “Previous campaigns have reached coverage in excess of 90%,” he says.

Victory in the battle against Ebola—to say nothing of the battle against measles—is by no means yet assured. But, again as the war colleges would teach, with the right cooperation and the right deployment, the good guys can win.

Correction: An earlier version of this story misidentified an assistant professor at the Johns Hopkins Bloomberg School of Public Health. He is Justin Lessler.

How Tetanus Shots Help Fight Brain Cancer

Patients who got the tetanus booster lived more than two years on average

Researchers who have harnessed the body’s immune system to fight cancer have found a way to make the approach work even better, using an ordinary tetanus vaccine.

They used their double-vaccine approach to greatly lengthen the lives of patients with one of the deadliest types of cancer — the brain tumor glioblastoma.

“Patients with glioblastoma usually survive for little more than one year. However, in patients who received the immunotherapy, half lived nearly five years or longer from their diagnosis,” said Dr. John Sampson of Duke University Medical Center, who oversaw the study.

7 Signs Your Child’s School Has Unvaccinated Students

The resurgence of the measles has drawn scrutiny to California’s fairly lenient vaccine policy, which allows parents to choose a personal-belief exemption to avoid vaccinating their kids. And while parents can send their non-inoculated children to school, the state also publishes detailed information on the vaccination rates at every public and private school in the state.

By comparing this information with characteristics of each school, we were able to draw a detailed picture of what sort of schools are attended by children of vaccine-skeptic parents. Here’s a breakdown by a few different school characteristics.

Vaccination rates go down with the percentage of students receiving free or reduced lunch—which is the best school-by-school economic indicator available. In other words: The better off the parents are, the more statistically likely they are to apply for personal-belief exemptions against the otherwise mandatory vaccinations.

Though it’s less commonly discussed, the religious affiliation of a school is also a useful predictor of vaccination rates. (As with all statistical correlations, this does not mean it is the religion that is dictating the choice not to vaccinate.) Baptist and Calvary Chapel schools are particularly likely to have unvaccinated students, though overall, private religious schools have higher vaccination rates than non-religious private schools.

And though they account for only 661 students, Waldorf schools (as identified by the name of the school) have extremely high rates of personal-belief exemptions, to the tune of 38 percent. Mother Jonescaught up with a dean at one such Waldorf school who explained that, while there was no recommended policy on vaccines, she was accepting of whatever choice parents made.

The raw data for this story is available for download on TIME’s GitHub account. The vaccination data was matched to public and private school registries as well as data on free and reduced lunch programs by school. The correlation between the percentage of students receiving free or reduced lunch and the rate of personal belief exemptions is -0.29, and the correlation with the number of enrolled students is -0.18.

Many Doctors Give In When Parents Want to Space Out Vaccines

The vast majority of doctors don’t believe that spacing out childhood immunizations is a good idea, but they’re doing it anyway. Here’s why

It’s an eye-opening survey, to say the least, and its findings are clear: Nearly all — 93% — primary care doctors and pediatricians surveyed say that in a typical month, parents ask them to deviate from the recommended childhood immunization schedule and instead give the shots over a longer period of time, according to a report published Monday in the journal Pediatrics. And while nearly 90% thought that such spacing out of the immunizations would put the children, and the community at risk of spreading infectious diseases like measles, 37% said they agreed to do so often or always. That was a 131% increase since the last survey, conducted in 2009, when only 16% said they agreed to changing the recommended vaccine schedule.

“Doctors are feeling really conflicted because they overwhelmingly think this is the wrong thing to do, and is putting children at risk, but at the same time, they want to build trust with their patients and meet people halfway,” says Dr. Allison Kempe, professor of pediatrics at University of Colorado and Children’s Hospital Colorado, who is the lead author of the study.

Even more concerning, she says, is the fact that 40% of the physicians said that the vaccine issue was the source of their job dissatisfaction. The survey also asked them about different strategies the doctors employed with parents to discuss the importance of following the existing vaccination schedule, but the doctors revealed very little confidence in those methods. In fact, the strategy they believed worked most often only garnered a 20% effectiveness rating, and that was telling parents that the doctors immunized their own children according to the recommended schedule.

“It’s a terrible conflict when I have to make a decision when I’m doing my vaccine orders for a particular child and decide if it’s going to be the pertussis vaccine for that infant or the Hib or the pneumococcal,” says Dr. Julie Boom, director of the immunization project at Texas Children’s Hospital and associate professor of pediatrics at Baylor College of Medicine, of the decision she has to make when parents insist on giving their babies only one immunization during a visit. While Boom makes every effort to discuss with parents the importance of sticking with the recommended immunization schedule, she says “I will offer the vaccine at that visit and explain the risks and benefits of the decision that parent is making and try to get them to come back as quickly as possible to take the next vaccine so the baby will be fully vaccinated as on time as possible.”

But she does that knowing that the baby leaves her office at higher risk of potentially getting sick since he is not fully immunized. “The baby leaving my office is at risk of getting the illnesses for which he’s not vaccinated,” she says. “To know I’m going to pick one [vaccine] and leave the other behind, despite all the time I spend explaining the risks and benefits to the parents—it’s very difficult for me.”

And it’s increasingly a problem for her colleagues as well. While parents who refused to vaccinate their children gained the most media attention in recent years and likely contributed to pertussis and measles outbreaks, even more parents – about 13% — used an alternative vaccine schedule that included delaying some of the shots. These parents often express concern about “overloading” their babies’ immune systems with too many shots in one visit (the most that infants generally get are five, at the year-old visit). In the survey, 35% of doctors said they realized that allowing parents to delay shots sent mixed messages; parents could interpret the action as proof that the existing schedule wasn’t so important after all if doctors ended up changing it.

Part of the conflict may come from the advice from organizations to which these physicians turn for help. As some frustrated doctors began to “fire” their patients and refuse to see them if they declined to vaccinate their children or asked for alternative immunization schedules, in 2005, the American Academy of Pediatrics advised its members to not dismiss those parents and urged them to discuss and educate them instead about the importance of vaccinations and of getting them on time. That may explain why 82% of doctors in the current survey said they felt agreeing to delaying some vaccines would build trust with their patients; 80% said that if they refused to accommodate the parents wishes, these parents would leave to find some doctors who would.

“Nobody is in favor of dismissing patients, but I think we need to get a little bit straighter about communicating to these parents about how strongly we feel about vaccinations, and how detrimental spacing them out is for their child,” says Kempe.

Among the most commonly used strategies to convince parents, doctors cited their comfort with vaccinating their own children according to the schedule, stressing that spacing out vaccines puts their children at risk of getting sick, reminding them of recent outbreaks of vaccine-preventable diseases, and explaining that alternative schedule haven’t been studied for their safety. Doctors have even informed parents that bringing their child back for multiple visits to get jabbed with a shot can be more painful for the baby. None were rated by the physicians as being more than 20% effective, leaving doctors at a loss.

That’s why professional organizations should take a stronger role in providing doctors with more guidance about what may work and what doesn’t. Conducting more studies on different methods of educating and addressing parents concerns could arm doctors with more data and scientific evidence to back up their belief in the established immunization schedule, for example. Kempe also notes that starting to educate parents earlier, such as during pregnancy, may help to reinforce their comfort with vaccines and what they can do to protect their baby once he is born. And reaching parents and parents-to-be on a more consistent basis may also be key to alleviating their concerns about vaccines. “We as doctors have not exploited mass media or the kinds of media that the anti-vaccine movement has,” says Kempe. “We are not doing a great job of countering the misinformation out there, and also not doing a good job of enlisting parents who are pro-vaccine in a proactive way to establish a social norm.”

Part of that has to do with the fact that the time that doctors typically have with parents during well-baby visits is short. Most doctors reported having to spend at least 10 minutes with parents to address their vaccine concerns; that’s about half of the time of an average visit, which also has to cover other important wellness issues such as nutrition, car safety, and more. So Kempe says other strategies, such as group visits or sessions to address vaccine questions specifically, or designated staff at family practices or pediatricians’ offices who are assigned the task of answering questions about vaccines and vaccine safety might be more effective. In Boom’s practice, she often schedules a separate visit for parents to discuss just their vaccine questions, so she doesn’t feel rushed to come to a decision about whether to help the parents space out vaccines or not.

For Boom, the key is understanding where the parents’ concerns come from. “For one parent it may be about long term effects of vaccinations, and for another it may be something else,” she says. “You have to understand where the misinformation is coming from, and then very specifically address each parent’s questions. It does take time.”

Using this strategy, Boom feels she is relatively successful in educating parents about the need to follow the recommended vaccination schedule. But she admits that working in an academic institution, she has the luxury or more time with her patients.

For those that don’t, it’s clear that frustration is reaching a boiling point in doctors’ offices. “I hope this study is a wake-up call, and I hope it’s time to say ‘okay, what we are doing isn’t working,’ and start asking ‘what should we be doing?’” says Kempe.

Feb. 23, 1954: The first mass inoculation of children against polio with the Salk vaccine takes place, in Pittsburgh

In the midst of the contentious debate between anti-vaxxers and those who side with mainstream science, it can be hard to imagine a time when Americans almost universally embraced vaccination.

That time was the 1950s, when the very real, utterly devastating effects of polio overshadowed any hypothetical questions of vaccine safety. In 1952, the worst polio outbreak in American history infected 58,000 people, killing more than 3,000 and paralyzing 21,000 — the majority of them children. As TIME reported, “Parents were haunted by the stories of children stricken suddenly by the telltale cramps and fever. Public swimming pools were deserted for fear of contagion. And year after year polio delivered thousands of people into hospitals and wheelchairs, or into the nightmarish canisters called iron lungs.”

When Dr. Jonas Salk’s vaccine debuted its first mass inoculation against polio on this day, Feb. 23, in 1954, the only fear most parents felt was that it wouldn’t become widely available fast enough to save their kids.

During its initial testing, the most salient safety question about Salk’s vaccine centered on the potential danger of injecting humans with monkey tissue. To make his vaccine, Salk’s team harvested kidneys from live monkeys and injected them with live polio virus, which quickly multiplied in the kidney cells. Then the team used formaldehyde to kill the virus before injecting it into humans.

But the traces of monkey kidney present in each dose of the vaccine were so minute that they posed no health risks, as Salk told the New York Times.

Instead, the greatest safety threat came not from monkeys but from human error: One of the labs licensed to produce the vaccine accidentally contaminated a batch with live polio virus in 1955. That batch killed five people and paralyzed 51.

With stricter oversight, however, the vaccine continued to be the lifesaver it was initially hailed as. Within the first few years, it cut polio cases in the U.S. by half. By 1962, the number of new cases had dropped to fewer than 1,000. And by the time of Salk’s death at age 80, 20 years ago, polio was already virtually extinct in the U.S. and dwindling worldwide.

Read the 1954 cover story about the polio vaccine, here in the TIME archives: Closing in on Polio

Facebook Must Shut Down the Anti-Vaxxers

Mark Zuckerberg should unfriend the crazies before more people get hurt

Mark Zuckerberg has never been famous for his reading choices. No one knows or cares if the founder of Facebook got around to Moby Dick when he was at Harvard. But in January, Zuckerberg launched an online book club, offering reading recommendations to members every two weeks. Earlier suggestions included such important works as Steven Pinker’s The Better Angels of Our Nature and Sudhir Venkatesh’s Gang Leader for a Day.

But Zuckerberg dropped something of a small bombshell with his most recent—and most excellent—choice, On Immunityby Eula Biss. It’s a thoughtful exploration of what’s behind the irrational fear and suspicion in the anti-vaccine community, as well as a full-throated call for parents to heed medical wisdom and get their kids vaccinated. “The science is completely clear,” Zuckerberg writes, “vaccinations work and are important for the health of everyone in our community.”

So kudos to Zuckerberg for getting the truth out and challenging the lies.

And shame on Zuckerberg for enabling those lies, too.

Social media sites can do an exceedingly good job of keeping people connected and, more important, spreading the word about important social issues. (Think the ALS Ice Bucket Challenge would have raised the $100 million it did for research into Lou Gehrig’s disease if people couldn’t post the videos of themselves being heroically doused?) But it’s long been clear the sites can be used perniciously too.

Want to spend some time in the birther swamp, trading conspiracy theories with people who absolutely, positively can tell you the Kenyan hospital in which President Obama was born? You can find them online. Ditto the climate-denying cranks and the 9/11 truthers.

But the anti-vaxxers have a particular power. People who buy the nonsense on a birther or truther page can’t do much more than join that loony community and howl nonsense into the online wind. Climate change denial is a little more dangerous because every person who comes to believe that global warming is a massive hoax makes it a tiny, incremental bit harder to enact sensible climate policy.

Anti-vaxxers, however, do their work at the grass-roots, retail, one-on-one level. Convince Mother A of the fake dangers of vaccines and you increase the odds that she won’t vaccinate Child B—and perhaps Children C, D or E either. And every unvaccinated child in her brood increases the risk to the neighborhood, the school, the community—the entire herd, as the epidemiologists put it. The multi-state measles outbreak that began in Disneyland, along with the epidemics of mumps and whooping cough in Columbus, Ohio and throughout California, have all been fueled by falling vaccine rates.

One thing that would help—something Zuckerberg could do with little more than a flick of the switch, as could Twitter CEO Dick Costolo and the other bosses of other sites—is simply shut the anti-vaxxers down. Really. Pull their pages, block their posts, twist the spigot of misinformation before more people get hurt.

The very idea of muzzling any information—even misinformation—will surely send libertarians to their fainting couches. Similarly, people who believe they understand the Constitution but actually don’t will immediately invoke the First Amendment. But of course they’re misguided. Is Facebook a government agency? No, it’s not. Is Zuckerberg a government official? No, he’s not. Then this is not a First Amendment issue. Read your Constitution.

It’s not as if the folks at Facebook aren’t clear about the kinds of things they will and won’t allow on the site, providing a brief listing and a detailed description of what are considered no-go areas. “You may not credibly threaten others, or organize acts of real-world violence,” is one rule, so nobody would get away with posting instructions for, say, how to build a pressure cooker bomb. There is nothing in the regulations that specifically prohibits trafficking in bogus medical information, but the first section of the policy statement begins, “Safety is Facebook’s top priority,” and then goes on to say “We remove content and may escalate to law enforcement when we perceive a genuine risk of physical harm, or a direct threat to public safety.” (Emphasis added.)

It’s worth wondering if Facebook would consider a page arguing that HIV does not cause AIDS and that therefore condoms are not necessary a threat to public safety. What about one that told teens that bogus research shows it’s OK to drive drunk if you’ve had no more than, say, three beers? If the site managers didn’t block these pages and a multi-car crack-up or a cluster of HIV infections occurred as a result, would they wish they they’d made a different decision? It’s hard to know. (As of publication time, Facebook had not responded to TIME’s request for a comment on, or further statement about, its policies.)

Facebook is equal parts town square, medium of communication and commercial bazaar—complete with ads. And it does all of those jobs well. What the site shouldn’t be is a vector for lies—especially lies that can harm children. Free speech is not in play here. This should be an easy call.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

Not so long ago (2011) the world was declared officially free of the cattle disease, rinderpest. As with the 1980 eradication of human smallpox, the basic weapon was vaccination. The rinderpest virus and measles virus are very similar, perhaps diverging from a common ancestor about 1,000 years back. We’ve had effective measles vaccines for around 50 years and the world could, and should, be rid of measles. But, apart from the problem of getting vaccine into war zones and other problems in very poor nations, we are nowhere near doing that. Why is that so?

Popular Among Subscribers

The latest outbreak associated with visitors to Disneyland is just one of continuing, sporadic events all over the advanced world. Measles is very infectious. Classically, a young, unvaccinated person is taken on family vacation to a country where the virus is actively circulating, contracts the disease and brings it back to spread rapidly in (often) an “alternative” school where there are many other unprotected children. Such schools are often the choice for intelligent, well-educated parents.

What’s happening with measles is a good example of the maxim that: “partial knowledge is dangerous.” In the main, people have a very limited understanding of infectious diseases. Viruses grow in cells and kill them. One virus particle is enough to initiate a full cycle of replication in what becomes a “factory” producing millions of progeny that are, in turn, released to go on and infect other cells. With influenza, the disease that I study, the successive cycles of infection, cell loss and inflammation are limited to the respiratory tract. That kills if the lung damage is sufficiently severe. With measles, though, the virus travels the body and can end up in any tissue.

Most 1st world citizens and doctors who are under 60 have never seen a case of measles. Those who do know anything about this disease understand that the kids get prominent skin spots. Each one of those red “lesions” reflects a focus of virus growth. The measles virus invades via the oropharynx, multiplies there and is then disseminated via the blood. The effects in the skin are obvious, but we don’t see what’s happening in the lung, the brain, the middle ear and elsewhere. The measles sequelae can include long-term hearing problems, persistent lung damage and (fortunately rare) the terrible disease subacute sclerosing panencephalitis (SSPE). In SSPE, a defective measles virus “hides out” in the brain, then suddenly re-emerges in adolescence. A fit teenager can suddenly go into a coma and die. SSPE disappeared with the widespread use of the measles vaccine. Nobody wants to see it return.

The measles vaccine is an “attenuated” virus strain that undergoes limited replication, infects few cells and does not disseminate widely via the blood. Given that the recommended immunization schedule has been followed, it provides long-lasting immunity.

So why does this vaccine get such a bad rap with some parents? Apart from a tendency of “empowered” adults to disregard medical advice and say “I will decide what is given to my child,” there are claims that injecting the measles, mumps rubella (MMR vaccine) is associated with the development of autism. This appeared in a 1998 paper by Andrew Wakefield and 12 others published in the prestigious British journal, The Lancet. The data set was just 11 cases, and the correlation was with MMR, not with the measles vaccine as such. There has been no confirmation, despite massive, international efforts to replicate the Wakefield et al findings. Major issues have been identified with the original Lancet paper, which has been retracted by the authors, excepting Dr. Wakefield. Apart from the tragedy that children are now needlessly contracting measles, the claim distracted those who are seeking a cause for autism, particularly some in the patient advocacy groups.

Why was this underpowered Lancet study so readily accepted? The thought that you might cause your child to develop autism is obviously horrific, and the problem with autism is that it often emerges around the age that children are receiving the standard vaccines. Listening to people arguing this case, it’s obvious that people will connect anything bad that happens to their kids back to vaccines given weeks, or even months previously. And the fact of the matter is that vaccination, like any medical procedure, has to be looked at through the lens of relative risk. There was a recent situation in Australia where an influenza vaccine was too “reactogenic,” causing fever and convulsions in a few very young children. The vaccine was quickly withdrawn and replaced by a safer product, with the event being thoroughly investigated by the US FDA and by the relevant Australian authorities. There were similar issues way back with whooping cough vaccines, which have been replaced by much “cleaner” products, though they are less effective in the immunity sense.

If, in reading this, you want to find out more, go online and watch the excellent NOVA documentary: Vaccines: Calling the Shots. Made by the Australian film-maker Sonya Pemberton, it first aired “down under” as Jabbed and was modified for a US audience. Then, I did my utmost to write an easily understood chapter on infection and immunity and how vaccines work in my recent (2013) Q&A book, Pandemics: What Everyone Needs to Know.

We all realize that parents want to do their best by their kids. That involves, though, not believing what some dubious and ignorant “celebrity” says on TV, but doing your utmost to understand the evidence and find out what is real. There is no virtue in ignorance, especially in deliberate ignorance that can compromise the wellbeing of children. Measles is highly infectious, and vaccination is a collective responsibility. According to the World Health Organization, some 145,700 children died of measles in 2013, with most fatal cases being in babies who are too young to be vaccinated and/or those with poor nutritional status. Who would want to be responsible for killing a vulnerable child?

Peter Doherty shared the 1996 Nobel Prize for Physiology or Medicine for illuminating the nature of the cellular immunse defense. He is a member of the Department of Microbiology and Immunology, University of Melbourne, Australia. You can find him on Twitter @ProfPCDoherty